The invention relates in general to a cutting insert that may be detachably mounted on a tool holder for cutting a work piece, and in particular to an indexable cutting insert having both positive and negative axially raked cutting edges for machining composite materials and the like.
Composite materials, such as fiber reinforced plastic (FRP) materials and the like, are widely used in aerospace industry due to its high specific strength and high specific stiffness. FRP materials are composite materials consisting of soft resin matrix and high strength fiber reinforcement. Typical fiber reinforcements include carbon fibers (CFRP), glass fibers (GFRP), Kevlar fibers, and the like. FRP materials are often processed into a laminated structure. FRP materials have excellent in-plane strength, but low inter-laminar strength. Unfortunately, it has been found that FRP materials tend to delaminate during machining using cutting inserts having only a positive axially raked cutting edge.